Deepak Unnikrishnan

Scalable network virtualization using FPGAs

Recent virtual network implementations have shown the capability to implement multiple network data planes using a shared hardware substrate. In this project, a new scalable virtual networking data plane is demonstrated which combines the performance efficiency of FPGA hardware with the flexibility of software running on a commodity PC. Multiple virtual router data planes are implemented using a Virtex II-based NetFPGA card to accommodate virtual networks requiring superior packet forwarding performance. Numerous additional data planes for virtual networks which require less bandwidth and slower forwarding speeds are implemented on a commodity PC server via software routers. Through experimentation, we determine that a throughput improvement of up to two orders of magnitude can be achieved for FPGA-based virtual routers versus a software-based virtual router implementation. Dynamic FPGA reconfiguration is supported to adapt to changing networking needs. System scalability is demonstrated for up to 15 virtual routers.

Customizing virtual networks with partial FPGA reconfiguration

Recent FPGA-based implementations of network virtualization represent a significant step forward in network performance and scalability. Although these systems have been shown to provide orders of magnitude higher performance than solutions using software-based routers, straightforward reconfiguration of hardware-based virtual networks over time is a challenge. In this paper, we present the implementation of a reconfigurable network virtualization substrate that combines several partially-reconfigurable hardware virtual routers with software virtual routers. The update of hardware-based virtual networks in our system is supported via real-time partial FPGA reconfiguration. Hardware virtual networks can be dynamically reconfigured in a fraction of a second without affecting other virtual networks operating in the same FPGA. A heuristic has been developed to allocate virtual networks with diverse bandwidth requirements and network characteristics on this heterogeneous virtualization substrate. Experimental results show that the reconfigurable virtual routers can forward packets at line rate. Partial reconfiguration allows for 20x faster hardware reconfiguration than a previous approach which migrated hardware virtual networks to software.

Application Specific Customization and Scalability of Soft Multiprocessors

Although soft microprocessors are widely used in FPGAs, limited work has been performed regarding how to automatically and efficiently generate soft multiprocessors.In this paper, an automated parallel compilation environment for multiple soft processors which incorporates parallel compilation and inter-processorcommunication structures is described. A total of eight previously-developed parallel processing benchmarks havebeen automatically mapped to a varying number of synthesized soft microprocessors in commercial FPGAs.The new automated infrastructure allows for an evaluation of area, performance, and power tradeoffs for a range of architectural choices. Experiments show that our soft-multiprocessor systems consisting of up to 16 processors can offer up to 5x improvement in application performance against their uniprocessor counterparts.

Reconfigurable Data Planes for Scalable Network Virtualization

Network virtualization presents a powerful approach to share physical network infrastructure among multiple virtual networks. Recent advances in network virtualization advocate the use of field-programmable gate arrays (FPGAs) as flexible high performance alternatives to conventional host virtualization techniques. However, the limited on-chip logic and memory resources in FPGAs severely restrict the scalability of the virtualization platform and necessitate the implementation of efficient forwarding structures in hardware. The research described in this manuscript explores the implementation of a scalable heterogeneous network virtualization platform that integrates virtual data planes implemented in FPGAs with software data planes created using host virtualization techniques. The system exploits data plane heterogeneity to cater to the dynamic service requirements of virtual networks by migrating networks between software and hardware data planes. We demonstrate data plane migration as an effective technique to limit the impact of traffic on unmodified data planes during FPGA reconfiguration. Our system implements forwarding tables in a shared fashion using inexpensive off-chip memories and supports both Internet Protocol (IP) and non-IP-based data planes. Experimental results show that FPGA-based data planes can offer two orders of magnitude better throughput than their software counterparts, and FPGA reconfiguration can facilitate data plane customization within 12 seconds. An integrated system that supports up to 15 virtual networks has been validated on the NetFPGA platform.

Configurable memory security in embedded systems

System security is an increasingly important design criterion for many embedded systems. These systems are often portable and more easily attacked than traditional desktop and server computing systems. Key requirements for system security include defenses against physical attacks and lightweight support in terms of area and power consumption. Our new approach to embedded system security focuses on the protection of application loading and secure application execution. During secure application loading, an encrypted application is transferred from on-board flash memory to external double data rate synchronous dynamic random access memory (DDR-SDRAM) via a microprocessor. Following application loading, the core-based security technique provides both confidentiality and authentication for data stored in a microprocessors system memory. The benefits of our low overhead memory protection approaches are demonstrated using four applications implemented in a field-programmable gate array (FPGA) in an embedded system prototyping platform. Each application requires a collection of tasks with varying memory security requirements. The configurable security core implemented on-chip inside the FPGA with the microprocessor allows for different memory security policies for different application tasks. An average memory saving of 63% is achieved for the four applications versus a uniform security approach. The lightweight circuitry included to support application loading from flash memory adds about 10% FPGA area overhead to the processor-based system and main memory security hardware.

Memory security management for reconfigurable embedded systems

The constrained operating environments of many FPGA-based embedded systems require flexible security that can be configured to minimize the impact on FPGA area and power consumption. In this paper, a security approach for external memory in FPGA-based embedded systems that exploits FPGA configurability is presented. Our FPGA-based security core provides both confidentiality and integrity for data stored externally to an FPGA which is accessed by a processor on the FPGA chip. The benefits of our security core are demonstrated using four embedded applications implemented on a Stratix II device. Each application requires a collection of tasks with varying memory security requirements. Our security core is used in conjunction with a NIOS II soft processor running the MicroC/OS II operating system. An average memory and energy savings of about 64%and 16%, respectively, is achieved for the four applications versus a non-configurable, uniform security approach.

High-performance hardware monitors to protect network processors from data plane attacks

The Internet represents an essential communication infrastructure that needs to be protected from malicious attacks. Modern network routers are typically implemented using embedded multi-core network processors that are inherently vulnerable to attack. Hardware monitor subsystems, which can verify the behavior of a routers packet processing system at runtime, can be used to identify and respond to an ever-changing range of attacks. While hardware monitors have primarily been described in the context of general-purpose computing, our work focuses on two important aspects that are relevant to the embedded networking domain: We present the design and prototype implementation of a high-performance monitor that can track each processor instruction with low memory overhead. Additionally, our monitor is capable of defending against attacks on processors with a Harvard architecture, the dominant contemporary network processor organization. We demonstrate that our monitor architecture provides no network slowdown in the absence of an attack and provides the capability to drop attack packets without otherwise affecting regular network traffic when an attack occurs.

ReClick - A Modular Dataplane Design Framework for FPGA-Based Network Virtualization

Network virtualization has emerged as a powerful technique to deploy novel services and experimental protocols over shared network infrastructures. Although recent research has highlighted field programmable gate arrays (FPGAs) as attractive platforms for high performance network virtualization, these devices remain inaccessible to the larger networking research community due to the absence of user-friendly programming models. A programming model that can abstract the intricacies of the hardware platform while being aware of the underlying resource constraints is highly desirable. In this paper, we present ReClick, a framework to efficiently design and deploy reconfigurable data planes for FPGA-based network virtualization systems. A hardware-agnostic programming model is described that allows developers to focus on the virtual data plane semantics rather than the implementation details. The framework exposes interfaces similar to the popular software router development framework, Click, and promotes design reuse. Optimization strategies are included in ReClick which use similarities between virtual data plane configurations to implement multiple planes in an area-efficient manner. Data planes exhibiting up to 1 Gbps data rate have been automatically compiled and tested in hardware in a Net FPGA platform.

Accelerating iterative algorithms with asynchronous accumulative updates on FPGAs

Iterative algorithms represent a pervasive class of data mining, web search and scientific computing applications. In iterative algorithms, a final result is derived by performing repetitive computations on an input data set. Existing techniques to parallelize such algorithms typically use software frameworks such as MapReduce and Hadoop to distribute data for an iteration across multiple CPU-based workstations in a cluster and collect per-iteration results. These platforms are marked by the need to synchronize data computations at iteration boundaries, impeding system performance. In this paper, we demonstrate that FPGAs in distributed computing systems can serve a vital role in breaking this synchronization barrier with the help of asynchronous accumulative updates. These updates allow for the accumulation of intermediate results for numerous data points without the need for iteration-based barriers allowing individual nodes in a cluster to independently make progress towards the final outcome. Computation is dynamically prioritized to accelerate algorithm convergence. A general-class of iterative algorithms have been implemented on a cluster of four FPGAs. A speedup of 7× is achieved over an implementation of asynchronous accumulative updates on a general-purpose CPU. The system offers up to 154× speedup versus a standard Hadoop-based CPU-workstation. Improved performance is achieved by clusters of FPGAs.

Securing Network Processors with High-Performance Hardware Monitors

As the Internet becomes integrated into nearly all aspects of everyday life, its reliability grows in importance. This vital communication resource, which has become an inviting target for attackers, must be protected with the same vigor as the end-systems it interconnects. Recent trends in network router architecture towards programmability and flexibility have increased the susceptibility of communication hardware to software attacks which modify intended data processing and forwarding functions. Contemporary routers typically feature network processors, whose protocol processing functions are determined via software. Prior work has shown that these general-purpose software-based processing systems can be attacked with data packets sent through the Internet. As a defense mechanism, the correct functionality of a network processor can be verified by a hardware monitor that observes processor operation and compares it to expected behavior. In the event of an attack, the monitor can interrupt the network processor, suppress malicious behavior, and reset the processor to a usable state for processing of subsequent traffic. In this work, we present several significant advances in hardware monitoring for network processors. A low-overhead monitor architecture that evaluates correct network processor operation in real-time on an instruction-by-instruction basis is described and tested. The monitor is shown to effectively prevent stack smashing attacks on processors that use a Harvard architecture, a widely used network processor configuration. Through experimentation, we show that our approach to hardware monitoring does not affect data plane packet throughput. In the event of an attack, malicious packets are dropped while packets of regular network traffic proceed through the network unaffected. A full evaluation of monitor architectural parameters is provided to create an optimized monitor design.